Apparatus and method for producing thermoplastic fibers



Oct. 21, 1952 M. A. CHAVANNES 2,614,288

APPARATUS AND METHOD FOR PRODUCING THERMOPLASTIC FIBERS Filed Ma rch 28, 1947 s Sheets-Sheet 1 IN VEN TOR.

MARQ /4.CHAM4NNES ATTORZYE Oct. 21, 1952 M. A. CHAVANNES APPARATUS AND METHOD FOR PRODUCING THERMOPLASTIC FIBERS 3 Sheets-Sheet 2 Filed March 28, 1947 @777 IEQN ATTOEZVE Oct. 21, 1952 M. A. CHAVANNES 2,614,288

APPARATUS AND METHOD FOR PRODUCING THERMOPLASTIC FIBERS Filed March 28, 1947 s Sheets-Sheet a FIG. I2

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\\ 5 M A. ZI /L aZS/VES ATTORNEY.

Patented @ct. 21, 1952 APPARATUS AND METHOD FOR PRODUCING THERMIOIPLASTIC FIBERS Marc A. Chavannes, New York, N. Y., assignor, by mesne assignments, to Chavannes Synthetic Fibres, End, a corporation of Delaware Application March 28, 1947, Serial No. 737,962

12 Claims.

The present invention relates to apparatus and a method for the production of fibers, filaments, threads and the like of thermoplastic material, and to the product of such method and apparatus.

Various methods in the past have been proposed for producing filaments of synthetic plastic materials. For example, one of these methods comprises an extrusion process. Numerous disadvantages have characterized these previous methods, however, such as very low speed of production, high cost, and limitations on the fineness of the filament which could be produced. Also, in extrusion processes difficulty has been found in incorporating pigments into the filaments, since a great many of the pigments have particles too large to be extruded through the small orifices required in order to produce very fine filaments or fibers. Moreover, in extrusion processes, drying of the filaments presents many technical clifiiculties.

A primary object of the present invention is to provide apparatus and a method for producing fibers, filaments, thread and the like of thermoplastic material rapidly, efilciently and economically. A feature of the present invention is that fibers of very small cross-section may be produced, and pigments may be incorporated directly into the fibers.

Another object of the present invention is to provide apparatus and a method for producing a series of fibers oriented with respect to each other so that they can be readily spun into thread or, otherwise operated upon without the necessity of certain heretofore-prevalent carding operations. Thus, for example, with this invention fibers may be delivered to a carrier belt oriented parallel to one another and staggered longitudinally with respect to one another.

Another object of the present invention is to produce fibers or filaments having desired shapes, with corresponding special properties. Also. multi-colored fibers and fibers of other special types may be produced.

The above-mentioned, as well as other objects, together with the many advantages obtainable by the practice of the present invention, will be readily comprehended by persons skilled in the art by reference to the following detailed description taken in connection with the annexed drawings which respectively describe and illustrate a preferred embodiment of the invention, and wherein Fig. 1 is a schematic elevational view of apparatus used in the present invention for producing fibers or filaments.

Fig. 2 is a plan view of one embodiment of the roller [6 in Fig. 1.

Fig. 3 is a greatly enlarged plan View of a portion of the roller shown in Fig. 2, together with plastic filaments formed thereon.

Fig. 4 is a greatly enlarged sectional View of a portion of the roller shown in Figs. 2 and 3, together with filaments formed thereon, the position of the section being indicated at 4--4 in Fig. 3.

Fig. 5 is a greatly enlarged plan view of a portion of another embodiment of the roller "[6 of Fig. 1, together with fibers thereon.

Fig. 6 is a greatly enlarged sectional view through the embodiment shown in Fig. 5, taken in the plane 6-6.

Figs. 7 and 8 are elevational and cross-sectional views, respectively, of a portion of a composite fiber including a strip of foil along one side thereof. The sectional plane is indicated at 8-8 in Fig. 7.

Figs. 9 and 10 are elevational and cross-sectional views, respectively, of another embodiment of a portion of a fiber having a strip of foil along one side thereof. 3

Figs. 11 and 12 are face and end views of a portion of a composite thermoplastic fiber comprising a plurality of lengths joined end-to-end, difierent lengths being of different color or composition. The position of the face view H is indicated at I l! I in Fig. 12.

Fig. 13 is a perspective view of a curly thermoplastic fiber.

Figs. 14 and 15 are elevational and end views of a composite fiber, comprising portions of different color or composition joined along their longitudinal edges.

Fig. 16 is an elevational view and Figs. 17 and 18 are cross-sectional views of a thermoplastic fiber of varying cross-section, the sectional planes being indicated at ll-l1 and l8l8 in Fig. 16.

To produce fibers or filaments by the teachings of the present invention, a preformed thermoplastic sheet, web or film may be employed, or such a film may be formed as an initial step in the process by means integrated with the film-forming apparatus. This film may be formed by calendering, or by "casting from a dispersion or solution of film-forming substance, or by other means. The film, which for example may be of a vinyl resin, is first heated to a temperature to render it soft and then is pressed in facewise engagement against an advancing irregular surface having channel-like regions adapted to form the softened film into fibers or filaments. The plastic material is cooled and set as it advances on the irregular surface, and then the resulting fibers or filaments are stripped from this surface. In a modification of the present invention the irregular surface may be adap ted to provide fibers which are staggered or otherwise oriented with respect to each other so as to be ready for spinning, and in some cases spinning apparatus may be integrated with the fiberforming apparatus.

In the illustrated embodiment there is provided an endless, continuously-advancing belt I0, which serves as a conveyor or carrier, and in certain regions serves as a pressure belt. The belt I may conveniently be of stainless steel. The belt l0 may be carried by a series of rotatable drums or rollers l2, I4, [6 and I8, which in turn are carried by a frame or other supporting means not shown. The roller l8 may be yieldingly urged in a generally outward direction to provide a tensioning effect on the belt [0. One of the rollers I2, I4, or it! may be positively driven to advance the belt [0 in a generally clockwise direction. The roller l6 may be positively driven to synchronize with the motion of the belt [0, or may be allowed to idle.

The roller l6 may be provided on its surface with a series of circumferential channels, and may be of metal, having said channels engraved therein. On the other hand, a particularly advantageous embodiment for this roller is as illustrated in Figs. 3 and 4. In this embodiment the effective surface of the roller is provided by a plurality of circumferentially arranged hoops of very fine wire 20, such as tungsten, embedded in adjacent relationship in a layer 22 of some metal such as lead, on the surface of the roller. A portion of this roller is indicated as l6a in Fig. 4. The wires 20 provide a hard, durable outer or work surface for the roller, and provide circumferential depressions between them where fibers may be formed. A series of such fibers 24 are shown in these depressions in Figs. 3 and 4. The metal 22 serves to bind the wires to the cylinder and the embedded arrangement makes this binding effect more secure and closes what might be termed the lower or inner nip between the wires.

In Figs. and 6 there is illustrated in plan and sectional views, respectively, another embodiment of a roller corresponding to the roller I6. In this embodiment, channels or grooves 25 wherein fibers 28 may be formed have been engraved in the surface l6b of the roller itself, as distinguished from the embodiment shown in Figs. 3 and 4 wherein the channels are formed between the adjacent wires.

The roller l6 may in some cases be adapted to produce continuous filaments. Thus in the embodiment illustrated in Figs. 3 and 4, assuming that the spaces between the hoops of wire are uninterrupted or completely circumferential, the filaments will be continuous. On the other hand, the roller It may in other cases, such as in the embodiment shown in Figs. 5 and 6, be adapted to produce'short fibers, oriented parallel to one another, but staggered longitudinally, for the purpose of making subsequent operations on the fibers easier. Thus certain carding operations may be eliminated, and the fibers may be more readily spun into thread if they are thus oriented. In order to fix the length of the .fibers, the engraved channels of Figs. 5 and 6 are terminated at their ends by transverse walls These walls may be staggered in relative position around the circumference of the roller, as shown in Fig. 5, so that the fibers will likewise be staggered.

The apparatus shown in Fig. 1 is provided with a source 32 of thermoplastic film 34. In case a preform film is employed, this source may merely comprise a reel from which the film is drawn. In case the film is continuously formed as an initial operation in this process, the source may comprise film-forming means, such as casting and drying apparatus, or calendering apparatus, or the like.

The film, after leaving the source, passes under a guide roller 36 and onto the continuously advancing belt H), which carries the film forward. There is provided a heating oven 38 extending through a considerable zone through which the belt [0 passes prior to passage over the roller 16. As the film 34 passes through this heating oven, it is heated until it becomes quite soft.

After passing over the roller M, the softened film is applied in facewise engagement to the channeled roller Hi. This roller is chilled, as by the introduction of a refrigerant through a pipe 40. It may be noted that the outer surface Illa of the conveyor belt is its inner surface as it passes around the roller 16.

There is provided at the roller 16 means for exerting pressure on the side of the belt hl opposite the film 34, adapted to squeeze the film between the belt and the roller l6 as they advance through an extended zone. Such means are schematically illustrated as comprising a series of rollers 42 yieldingly urged toward the belt by spring means 44 carried by a frame 46.

It is important that the pressure exerting means just described be adapted to exert pressure at the position T where the film first comes into contact with the chilled roller l6. Otherwise the film may become chilled to such an extent that it becomes set before it can be formed or moulded into fibers. Portions of the warm softened film are pressed by the belt i0 down into the channels or grooves of the roller Hi. It is important that the high regions of the roller it, such as the wires 20 in Figs. 3 and 4 or the ridge-like regions 48 in Figs. 5 and 6, pass completely through the film so as not to leave any membrane portions or the like interconnecting the portions which are forced down into the channels. Thus the device should function so that all portions of the film are forced into the various channels. The film should bevery soft, being in approximately a semi-fluid stage when this operation is taking place, and for this reason it is possible for the aforementioned high regions of the roller l6 to pass completely through the film. Actual contact should be made between the belt I0 and the high points of the roller l6. Because of the feature of avoiding membranes interconnecting the fibers or filaments, the film must be no thicker than can be accommodated by the channels, this means that the channels should be deeper than the thickness of the film employed, since they must accommodate portions of the film adjacent the high regions of the roller in addition to those portions of the film immediately above the channels. As illustrated in Fig. 6, the channels may in some embodiments be deeper than necessary to accommodate all of the softened plastic substance, and in such cases they will be only partially filled. As the portions of softened film enter the channels, they quickly become chilled, and

hence they quickly become set and form the desired fibers or filaments.

The shape of these fibers or filaments will be partly determined by the shape of the channels, and partly determined by surface tension effects, which tend to draw the fibers into a somewhat circular cross-section. One feature of the present invention is that it is possible to form fibers having rounded ends and rounded cross-sectional shapes. Such fibers are to be distinguished from bodies produced by processes wherein a long filament is cut into a number of short segments. This cutting step tends to produce ends having sharp corners, Fibers produced by the present invention are similarly different from articles which might be produced by shredding a sheet of plastic material. Shredding processes would produce fibers having sharp longitudinal edges, and furthermore it would probably be very olifiicult, if not impossible, to shred sheets into fibers as fine as the fibers which can be produced by the present invention. The product of the present invention is also different in a number of other respects from products of other processes.

The channels of the roller It should not include undercut regions, since such regions would make it very difiicult to remove the fibers.

A variety of cross-sectional and longitudinal shapes may be employed for the channels, in order to give the fibers various desired shapes. Thus, for example, the channels may be V-shaped in cross-section, or rectangularly shaped. It is also possible by the present invention to produce a fiber of non-uniform cross-section. An example of such a fiber is shown in Figs. 16, 17, and 18.

In longitudinal section the fibers may have a somewhat wavy or curved shape to produce the special effects such as, for example, a curly eifect. A curly fiber is shown in Fig. 13.

In some cases the high regions of the roller I6 may have the shape of rather sharp ridges, to make it easier for them to pass completely through the film.

As the belt it! leaves the roller It, the fibers are removed from the roller and the belt, and the belt I passes around the roller I8 and returns to the roller I2.

Various means may be provided for removing the fibers from the roller I6. One such means, illustrated in Fig. 1, makes use of static electricity to attract the fibers. There is provided a belt 50 of dielectric or non-conducting material such as rubber. This belt is carried by a series of rollers 52, one of which may be positively driven and adapted to advance the belt 50 in a generally clockwise direction. The belt 50 should preferably extend close into the nip where the belt III leaves the roller I5. There is provided means for placing an electric charge on the belt 50. Such means may be in the form of a felt buffer 54 rotating in a direction to oppose the motion of the belt B. At a later point in the path of travel of the belt 50 there is provided means for removing the charge from this belt. Such means are shown schematically in the form of a grounded roller 56. In operation, the belt 59 passes by the bufier 5d, receives an electric charge therefrom, then passes by the roller I6, where it attracts the fibers to it by electrostatic attraction. There may be provided a scraper or comb 51 engaging the roller It and adapted to assist in removing the fibers from this roller. The belt 50 then passes over the grounding roller 56. The speed of the belt 50 may be con- 6 trolled to have a predetermined ratio to the speed of the roller I6. In the present example it may be assumed that they move at equal linear speeds. In this case, the fibers on the belt 50 will have an orientation similar to' that which they have on the roller I6.

There may be provided'another belt 58 supported slightly above the belt 50 andadvanced in a generally clockwise direction by suitable rollers. One of such rollers is shown at 60. This belt is adapted to carry the fibers forward into other apparatus 62, such as spinning apparatus. The belt 58 may, like the belt 50, be'of dielectric material, for example, rubber. There may be provided means for placing an electrostatic charge on the belt 58, such as a buffer 64. The belt 58 is adapted to pick up the fibers from the belt 5!), particularly in the zone immediately to the right of the grounding roller 56, where the fibers will no longer be attracted to the belt 50 but will be attracted to the belt 58 because of the charge thereon.

The belt 58 may in some embodiments be advanced at a speed slower than the speed of the belt 50. This will have the effect that the layer of fibers on the belt 58 will be thicker than the layer of fibers on the belt 50. The thicker layer of fibers may then be advanced into the apparatus 62 for spinning or other operations. For certain operations the increased thickness of the layer of fibers thus provided by the difference in speed between the belts 50 and 58 is quite desirable.

The controlled orientation of the fibers produced by the present apparatus may prove highly advantageous in eliminating certain carding operations which would otherwise be necessary.

A variety of modifications of the present invention are possible. For example, if a colored film is used, it is possible to produce individual fibers which have portions of different colors. If the film is provided with stripes which run transverse to the grooves of the roller I6, the individual fibers produced may each comprise a plurality of differently colored lengths, joined end to end, as shown in Figs. 11 and 12. If a multicolored film is used having stripes running parallel to the direction of the grooves in the roller I5, and if the stripes are of considerably greater width than the width of the fibers, there may be produced some fibers of one color and some fibers of another color. If instead of producing very fine fibers, strands of somewhat. larger cross-section are produced, it may be practical to employ a multicolored film having longitudinal stripes comparable in width to the width of these strands. In this case, if the stripes are placed so that the dividing line between stripes passes along the length of a strand, then this strand will comprise two difierently colored elongated portions, joined along their longitudinal edges. Figs. 14 and 15 show a fiber comprising two differently colored portions, the portions extending longitudinally of said fiber in a side-by-side arrangement.

Since in the present process the fiber being formed is supported by the grooved surface until it becomes firm or set, the present process is a highly advantageous one, and produces a unique product. The supporting action mentioned makes it possible by the present invention to produce an extremely fine fiber, smaller than a silk fiber. A special feature of the invention is that it is possible to employ in the fibers particles of pigment the cross-sectional areas of which'are so 7 great in proportion to the cross-sectional area of the fiber that it would be impossible in apparatus for extruding fibers through an orifice, to use pigment particles of this relative size.

The apparatus of the present invention lends itself readily to integration with spinning apparatus. In a special embodiment of the present invention it is possible to'calculate the thickness and width of the film, the width of the grooved roller, and the shape and spacing of the grooves in relation to one another so that there is produced a band of fibers just sufficient to be spun into a single thread. Alternatively, the film may correspond to an integral number of threads, and means may be provided for guiding the fibers as they leave the grooved roller onto a corresponding number of belts, and thence into a plurality of spinning machines, each machine being fed by one such belt and adapted to produce one thread.

It is possible by the teachings of the present invention to produce a plastic fiber having a strip of metallic foil extending lengthwise of same and bonded thereto. A thermoplastic film may first be formed on a sheet of foil and dried. This film, laminated to the foil, may then be passed through the present apparatus, and it may be seen that the product just described will be produced. One embodiment of such a product is shown in Figs. 7 and 8. The foilis indicated as 64, and the plastic portion of the fiber is indicated as 55. Another embodiment of such a product is shown in Figs. 9 and 10, the foil being indicated as 68 and the plastic portion of the fiber as 10.

It will be understood that the term fibers as used in the appended claims, is intended to be broad enough to include either a continuous strand-like fiber, or a fiber of limited length.

While a suitable form of apparatus and mode of procedure, to be used in accordance with the invention, and various improved products resulting therefrom have been described in some detail, and certain modifications have been suggested, it will be understood that numerous changes may be made without departing from the general principles and scope of the invention.

I claim:

1. A method for producing fibers, comprising superposing a continuous web of thermoplastic film on a continuously-advancing carrier, preheating said film while on said carrier to soften it to a semi-molten state, subsequently advancing said hot film and carrier through an arcuate path, applying pressure at all points throughout the length of said arcuate path to parallel, 1ongitudinally-extending areas of the exposed surface of said film while said film is hot and in a semi-molten state, to divide said film into fibers, cooling said fibers before releasing said pressure, releasing said pressure, and stripping said fibers.

2. A method for forming fibers, comprising applying a film of thermoplastic material to a continuously-advancing flexible carrier, softening said film with the aid of heat by advancing said film and said carrier through an elongated heating zone, thereafter advancing said carrier and hot, soft film along an arouate path, applying pressure against parallel areas extending longitudinally of said film as it advances along an extended portion of said arcuate path to mould said film into fibers of thermoplastic material, said film being hot and soft upon initial application of said pressure, chilling said fibers as they advance along said path, and thereafter stripping said fibers.

3. A method for producing fibers, comprising applying a continuous, thermoplastic film to a continuously-advancing, flexible, carrier belt, preheating said film while on said carrier to soften it to a layer of semi-fluid substance, flexing said layer in such a direction that its surface away from said carrier is concave, as viewed in longitudinal section, moulding said layer of semifiuid substance into fibers thicker than said film having a substantially fiat side and two concave sides, joined by rounded edges, by applying pressure to parallel areas of the surface of said film opposite said carrier, cooling said fibers to set them, and stripping said fibers from said carrier.

4. A method of forming fibers comprisin advancing a relaxed thermoplastic film on a carrier through a heating zone, heating said film sufiiciently to soften same to a non-self-supportable layer of semi-fluid substance, dividing said layer of semi-fluid substance into elongated bodies thicker than said film, and moulding said bodies to have a substantially flat side and two approximately concave sides joined by rounded edges by applying pressure to said bodies with respect to said carrier in paired adjacent areas of curved cross-section.

5. A method of forming fibers of a type that different parts of individual fibers are of different composition, comprising heating a composite film of thermoplastic material to soften same, maintaining said film in a softened state while applying localized pressure to its opposite surfaces in generally parallel regions to divide said film into fibers, said film having parts of different composition within the zones thereof which form individual fibers.

-8. A method of forming fibers comprising a thermoplastic material and a strip of foil extending along the length of said fiber, bonded thereto, said method comprising adhering a thermoplastic film to a layer of foil, to form a composite web of a plurality of layers, different layers being of different composition, and dividing said web into generally parallel fibers, with the aid of heat and localized pressure against opposite surfaces of said composite web.

'7. A method of forming fibers comprising a plurality of lengths of different composition, joined end-to-end, said method comprising the steps of heating a thermoplastic film comprising stripe-like portions of different composition, and dividing said film into individual fibers by the use of heat and the application of localized pressure to said film along lines extending across said stripes.

8. Apparatus for forming fibers of thermoplastic material, comprising a continuously-advancing carrier, a grooved roller, said carrier embracing said roller through an extended are, means at a station prior to said roller, for applying a thermoplastic film to the surface of said carrier which is opposed to said roller, an elongated film-softening oven located between the point of application of said film to said carrier and said roller, the exit of said oven being located close to said roller to cause said film to be in a semi-molten condition when it reaches said roller, means pressing said carrier toward said roller at points located along an extended arc, including the point where said carrier is initially opposed to said roller, said roller being adapted to mould said hot, soft film into fibers thicker than said film, means for cooling said fibers, and means for stripping said fibers.

9. Apparatus as in claim 8 including means for chilling said roller.

10. Apparatus for forming fibers comprising an advancing carrier, meansior applying a thermoplastic film to said carrier, an oven adapted to heat said film to a semi-fiuid state, a roller provided with a plurality of adjacent circumierential hoops of circular cross-section having grooves therebetween, said grooves being deeper than the thickness of said film, said roller being adapted to engage said film on said carrier and to divide it into elongated bodies having at least one diameter greater than the thickness of said film and to mould said bodies to have a substantially flat side adjacent said carrier and two approximately concave sides adjacent said hoops, said sides being joined by rounded edges.

11. Apparatus for forming fibers comprising a plurality of lengths of different composition, joined end-to-end, said apparatus comprising an advancing carrier, means for applying to said carrier a thermoplastic film having stripe-like portions of different composition with the stripes running across said carrier, means for heating said film to a softening point, and a roller engaging said carrier having circumferential grooves running longitudinally of said carrier adapted to divide said film along lines extending across said stripes.

12. Apparatus for forming composite fibers, comprising means for adhering thermoplastic film to a layer of foil to form a composite web of a plurality of layers, heating means adapted to render said thermoplastic material soft, a

' grooved roller and a carrier adapted to engage said web on opposite sides and to divide said composite web into composite fibers.

MARC AL. CHAVANNES.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,773,969 Dreyfus Aug. 26, 1930 1,880,110 Shapiro Sept. 27, 1932 1,964,659 Brumberger June 26, 1934 1,992,279 Arni et a1. Feb. 26, 1935 2,090,560 Ubbelohde Aug. 17, 1937 2,143,627 Knowland Jan. 2, 1939 2,152,826 Spencer Apr. 4, 1939 2,185,789 Jacque r Jan. 2, 1940 2,254,233 Meyer Sept. 2, 1941 2,276,608 Bugge Mar. 17, 1942 2,289,774 Graves July 14, 1942 2,289,775 Graves July 14, 1942 2,337,969 Bugge Dec. 28, 1943 2,370,112 Truitt Feb. 20, 1945 2,434,533 Wurzburger Jan. 13, 1948 FOREIGN PATENTS Number Country Date 2,939 Great Britain Mar. 26, 1903 

